Right Gen.P6zamani, let's go.
Here are the answers to your questions:
Question 5:
The question text for this item is cut off, but based on the options comparing Li, Na, and K, it likely asks about a periodic trend such as atomic radius or ionization energy. Assuming it asks for the order of increasing atomic radius for these Group 1 elements:
Atomic radius increases down a group in the periodic table. Therefore, the order of increasing atomic radius is Li<Na<K.
The correct option is A) Li < Na < K.
Question 6: What is the empirical formula of a compound containing 40% C, 6.7% H, and 53.3% O?
Step 1: Assume a 100 g sample to convert percentages to mass.
Mass of C = 40 g
Mass of H = 6.7 g
Mass of O = 53.3 g
Step 2: Convert mass to moles using atomic masses (C ≈12.01 g/mol, H ≈1.008 g/mol, O ≈16.00 g/mol).
Moles of C:
12.01g/mol40g≈3.33mol
Moles of H:
1.008g/mol6.7g≈6.65mol
Moles of O:
16.00g/mol53.3g≈3.33mol
Step 3: Divide by the smallest number of moles to find the simplest mole ratio.
The smallest number of moles is approximately 3.33 mol (for C and O).
Ratio for C:
3.333.33=1
Ratio for H:
3.336.65≈2
Ratio for O:
3.333.33=1
Step 4: Write the empirical formula using these ratios.
The empirical formula is CH2O.
The correct option is A) CH2O.
Question 7: Which of the following gases is a noble gas?
Noble gases are elements in Group 18 of the periodic table, characterized by a full outer electron shell, making them very unreactive.
- A. Chlorine (Cl2) is a halogen (Group 17).
- B. Neon (Ne) is a noble gas (Group 18).
- C. Oxygen (O2) is in Group 16.
- D. Nitrogen (N2) is in Group 15.
The correct option is B) Neon.
Question 8: Which ion has the same electron configuration as Argon?
Argon (Ar) has an atomic number of 18, meaning it has 18 electrons. We need to find the ion(s) with 18 electrons.
- A. K+: Potassium (K) has 19 electrons. K+ means it has lost 1 electron, so 19−1=18 electrons.
- B. Ca2+: Calcium (Ca) has 20 electrons. Ca2+ means it has lost 2 electrons, so 20−2=18 electrons.
- C. Cl−: Chlorine (Cl) has 17 electrons. Cl− means it has gained 1 electron, so 17+1=18 electrons.
All three ions (K+, Ca2+, Cl−) have 18 electrons, which is the same electron configuration as Argon.
The correct option is D) All of the above.
Question 9: Which bond is most polar?
Bond polarity is determined by the difference in electronegativity between the two bonded atoms. A larger difference results in a more polar bond.
- A. H−H: Electronegativity difference is 0 (nonpolar).
- B. H−Cl: Chlorine is significantly more electronegative than hydrogen, leading to a polar bond.
- C. Cl−Cl: Electronegativity difference is 0 (nonpolar).
- D. O−O: Electronegativity difference is 0 (nonpolar).
Among the given options, H−Cl is the only polar bond and thus the most polar.
The correct option is B) H-Cl.
Question 10: In electrolysis of molten NaCl, what is formed at the cathode?
In the electrolysis of molten sodium chloride (NaCl), the only ions present are Na+ and Cl−.
- The cathode is the negative electrode, where reduction occurs (gain of electrons). The positively charged Na+ ions are attracted to the cathode.
Na+(l)+e−→Na(s)
Therefore, sodium metal is formed at the cathode.
- The anode is the positive electrode, where oxidation occurs (loss of electrons). The negatively charged Cl− ions are attracted to the anode.
2Cl−(l)→Cl2(g)+2e−
Therefore, chlorine gas is formed at the anode.
The correct option is B) Sodium metal.
Send me the next one 📸